Prior art web feeding machines of the type adapted to handle rolls of preprinted paper for delivery to or reclamation from a laser printer have evolved into relatively complicated structures with all the inherent disadvantages of these complications. For example, the machine shown in prior art U.S. Pat. No. 5,000,394 includes an elevator structure for lifting the paper roll into position by means of a vertically mounted carriage including laterally movable arms for engage the end of the paper roll core. Changes in the speed of the paper web to accommodate changes in speed of the laser printer are also available and have taken the form of a tension free loop in the paper web between the printer and the paper roll. The paper roll is generally driven by a relatively short pair of belts provided in a pivoted arm structure that drives the roll peripherally to provide the web from the bottom of the roll, over a series of rollers to form the tension free loop. The speed of the belts is controlled by an ultrasonic detector so located as to sense the depth of the tension free loop. A control circuit uses this information to regulate the speed of the drive belts and hence the rate at which the web travels.
In a typical installation where paper web is to be fed at widely varying speeds to a laser printer unwind stands of this general type often require replacement of these drive belts. The present invention seeks to minimize the downtime required on such a machine by providing for expeditious replacement of such belts by reason of the fact that only one such belt is required in the unwind machine to be described, and also because the belt itself can be readily slackened to permits its removal for replacement purposes.
In machines for reclaiming or rewinding the paper web discharged from a laser printer or the like there is a need for providing a constant tension in the web material being rewound on the roll while at the same time maintaining a tension free loop between the rewind machine and the utilization device or laser printer. The paper roll in such a rewind machine is generally driven by one or more driven rollers rather than by drive belts. The present invention provides a unique path of travel for the web so as to maintain this tension in the web as it is rewound on the roll. An important feature of the present invention is that the paper web is wrapped around a significant peripheral portion of a friction roller provided in the machine for this purpose. The friction roller permits at least one tension free loop to be formed between the laser printer and the rewind machine without sacrificing the tension in the paper web between such friction roller and the roll of paper being rewound. Such friction rollers tend to wear however, and hence removal of the friction roller for replacement or for repair is often necessary. The machine to be described meets this need.
Among the objects of the present invention then are to provide a less complicated, less expensive machine for winding, and a machine for rewinding paper, fed to or received from a utilization device such as a laser printer. Since the paper rolls normally handled by such machines are quite heavy, on the order of 750 to 1500 pounds, it is generally necessary to provide for hydraulic hand trucks or the equivalent to move these paper rolls from one area of a typical printing installation to the vicinity of the laser printer. Furthermore, the typical hydraulic hand cart can be utilized to lift the paper rolls into or out of rewind and winder machines without the need for the machine itself providing a mechanism for lifting the roll. Recognition of this fact has led to the uncomplicated, and hence lower cost winder and rewinder machines to be described.
Another important feature of the present invention can be traced to the accommodation of conventional pneumatic air shaft for supporting the roll of paper in the machine frame, As a result of preassembling such a pneumatic roll core shaft with a paper roll prior to installation of the combination in the machine, the machine itself can be less complicated leading to less downtime and hence improves productivity for the overall combination of unwind machine laser printer and rewind machine.